Webster’s Revised Unabridged Dictionary · 1913
Telharmonium
Tel′har·mo′ni·um, n. [Gr. τῆλε far + harmolium.] An instrument for producing music (Tel·har′mo·ny [?]), at a distant point or points by means of alternating currents of electricity controlled by an operator who plays on a keyboard. The music is produced by a receiving instrument similar or analogous to the telephone, but not held to the ear. The pitch corresponds with frequency of alternation of current.